As a side project, 22-year-old computer whiz Aktarer Zaman built a website called Skiplagged, which searches out cheap airfares, particularly a type of cheap airfare called Hidden City that is frowned upon by the airlines. Last month, United and Orbitz filed a lawsuit trying to shut his website down, Bloomberg reported at the time. In the lawsuit, United and Orbitz call Skiplagged “unfair competition” and say it promotes “strictly prohibited” travel, reports CNN Money’s Patrick Gillespie. They’re asking for $75,000 in damages. But instead of bowing, he’s fighting.

So far, he’s raised almost $33,000 with the total raising every minute, thanks to all the press attention this lawsuit has gotten. (In the time it took us to write the post, the total raised grew from $14,000 to $17,000.)

“I really don’t know how much this lawsuit is going to ultimately cost, other than probably a lot,” he told donors on GoFundMe. “However, you have my word that how every cent is spent will be posted here. If there are any remaining funds, those will be completely donated to charity. I haven’t decided which yet, but if you have any suggestions, do send me a message.”

Hidden City travel is when you book a longer flight that includes a layover to your real destination because it’s cheaper than flying direct. You travel with carry-on and you get off the plane during the layover.

Travelers feel that this is a perfectly fair, legit way to travel: They’ve paid for the flight—why does the airline care if they sit in the seat the whole time? But airlines frown on it. They want you to pay rates according to their complicated pricing schemes. They argue that booking a flight like this makes it difficult to track passengers and that it unfairly takes advantage of the hub-and-spoke nature of airfares, where airlines fly to hub cities and add connecting flights from there.

Anyone can search and book his own Hidden City flights, but it’s a time-consuming mess to search through many cities, hoping to find a cheaper flight that has a layover at your true destination. Skiplagged does that searching for you. And finding such a flight isn’t a given. Often it tells you that there are no lower-cost Hidden City flights available that fit your travel needs.

As you might imagine, airlines hate this practice. If the airline discovers that you are getting off the airplane at a layover, it might cancel the ticket without refund, reports Bloomberg. It may do other things, too, like void frequent-flyer mileage.

Zaman told CBS News that his site merely shows the airfares, it doesn’t book the tickets. “I haven’t made any money from this,” Zaman said. He’s been paying for the costs of the website out of his own pocket. But now, the Internet has taken an interest and people are opening up their wallets to help with his legal fight.

United sent us this statement: “This practice violates our fare rules, and we are taking action to stop it to help protect the vast majority of customers who buy legitimate tickets.”

An Orbitz spokesperson told us that Zaman had found a way to help Skiplagged’s visitors book the flight directly on Orbitz.

“Skiplagged had developed technology that provided a direct link to our booking engine. So when it had identified a hidden city itinerary there was a ‘book now’ button that the customer clicked, directed them to Orbitz and then we processed the transaction not knowing the intent of the customer,” a representative told us. “We asked Skiplagged to disengage that link but they originally declined. We have since blocked the link and I believe the link to Orbitz is no longer displayed.”

The Orbitz representative also told us if some airlines catch a passenger on “a hidden-city routing, that ticket will be voided consistent with published fare rules and a refund will not be authorized.”

The representative explained, “While some independent operators might encourage consumers to try to break ticketing rules, we have an obligation to uphold airline fare rules and also protect consumers from making purchases that could be invalidated.”

We’ve reached out to Zaman.

Here’s a chart posted by Skiplagged that shows how often Hidden City fares are cheaper than longer fares on a flight in August between Seattle and New York.